Safety knife bar latch for paper cutters



F. BARNEY Sept. 2, 1941.

SAFETY KNIFE BAR LATCH FOR PAPER CUTTERS Filed Aug. 19, 1940 6 I o M .7 W M o m m 2 u v ,1

\nvefi'o Freeman T5 Patented Sept. 2, 1941 UNITED STATES PATENT Q' -FICEH SAFETY KNIFE BAR LATCH FOR PAPER CUTTERS Freeman Barney, Spring Lake, Mich, assignor to The Challenge Machinery Company, Grand Haven, Mich., a corporation of Michigan Application August 19, 1940, Serial No. 353,184

Claims.

This invention relates to a safety knife bar latch for paper cutters and more particularly for paper cutters in which the knife is operated by a hand lever.

The object of the invention is to provide a simple, durable and efiicient safety latch which is hand operated and requires the operator to use one hand to unlatch the knife bar and the other hand to operate it so that there will be no danger of getting his fingers cut by the knife when it is operated.

The invention provides various novel features of construction and arrangement as will be hereinafter more fully described in the accompanying claims.

Fig. 1 is a front elevation of a paper cutter having the safety latch embodying this invention applied thereto.

Fig. 2 is an enlarged fragmentary elevation of a part of the machine with the safety latch applied.

Fig. 3 is a fragmentary sectional elevation on the line 3-3 of Fig. 2, and

Fig. 4 is a fragmentary sectional plan on the line 44 of Fig. 2.

Like numbers refer to like parts in all of the figures.

The paper cutter to which the safety latch is applied is of conventional form having a frame I, a work table 2, the knife bar 3, the knife 4 attached to the knife bar and other conventional parts.

The knife and knife bar are moved downward diagonally by a hand lever 5 fixed to a shaft 6 on which is a lever 1 which is connected by a link 8 to the knife bar. The opposite ends of the knife bar are guided in their movements by links 9 pivoted respectively to the knife bar and to the frame.

The safety latch comprises a body I0 pivoted to the frame I adjacent the path of movement of the knife bar 3, a shouldered stud ll being screwed into the frame I and passing through the body of the safety latch 10 and acting as a pivot. The lower edge of the knife bar 3 is beveled and a shoulder l2 on the safety latch body l0 extends under and into engagement with thelower edge of the knife bar 3 when it is in raised position. The body l9 also has a projecting stop l3 which will engage the Vertical face of the knife bar 3 when the shoulder I2 is beneath the knife bar to limit movement of the latch and a finger grip H5 is provided on the body It! by means of which the latch may be manually operated. A forwardextends over a shoulder la. on the frame I and a plunger 16 is mounted in an opening in the extension l5 and is thrust downward by a spring IT. The plunger it engages the shoulder Ia on the frame and tends to swing the latch toward the knife bar 3.

In operation, when the knife bar is in raised position the plunger It will move the latch bar so that the shoulder I2 is under the beveled lower edge of the knife bar 3 and the stop I3 is against the vertical face of the knife bar. In this position the latch prevents downward movement of the knife bar. The machine is operated by the right hand of the operator which grasps the lever 5 and at the same time the operator must release the safety latch by gripping the finger piece I 4 with his left hand to swing the shoulder I3 from under the latch bar. When this is done the knife bar and knife may be lowered to cut through the paper beneath it and in so operating the machine both hands of the operator are occupied and cannot be engaged by the knife. When the knife is again raised to its upper position and the safety latch released the plunger It will move the shoulder l2 under the knife bar.

I claim:

1. The combination with a paper cutter having a frame, a knife bar and knife and means for actuating the knife manipulated by one hand of the operator, of a safety latch comprising a body pivoted to said frame adjacent the path of the knife bar, a shoulder on said body adapted to move under the knife bar to prevent downward movement thereof, spring means acting to move said shoulder under said knife bar and a finger grip by which the latch may be released from said knife bar under tension of said spring means.

2. The elements in combination defined in claim 1 combined with stop means on said latch engageable with the vertical face of said knife bar to limit the movement of said shoulder under said knife bar.

3. The elements in combination defined in claim 1 in which the lower edge of said knife bar is beveled and said shoulder engages said beveled edge of the knife bar.

4. The combination with a paper cutter having a frame, a knife bar and knife and means for actuating the knife manipulated by one hand of the operator, of a safety latch comprising a body pivotally mounted on a vertical face of said frame adjacent the path of movement of the knife bar, a shoulder on said body adapted to move under said knife bar, a forward extension on said body 1y projecting and offset portion I5 of the body it) having an opening, a spring actuated plunger in said opening engaging said frame and acting to claim 4 in which the lower edge of said knife bar thrust said shoulder under said knife bar, a finger is beveled and said shoulder on the latch body is piece on said body for manual manipulation and inclined corresponding with said beveled lower a stop on said body engageablewith the vertical edge of the knife bar.

face of the knife bar. 5 FREEMAN BARNEY.

5. The elements in combination defined in 

